Ben Wallace is a great defender but not one on one. That's why Detroit has Rasheed guard Duncan. If Ben was to be on Duncan, he would get punished inside. Because Ben is on the weak side, he can come help any perimeter defender that gets beat. That and rebouding is all he does.
Bowen on the other hand, is a shut down guy. Any player going against already has it in their heads that they are in for a tough night. Instead focusing on the game, they will try and be superman and try to dominate Bowen. Their whole game is then out of the window because they will never succeed in dominating Bowen. That's why you hear the es whining about Bowen in the media. i.e Dirk, Carter, Allen. They are used to scoring against anybody and when they are not succeeding, they resort to ing.
Bowen is a game changer because he shuts down a player, which changes the game. Ben is simply a help defender. He can also be a game changer if he constantly gets blocks and rebounds, but that doesn't always work. I think many know that Ben's defensive game this year has been worse than previous years. When Dwayne Wade was torching the pistons this season, Ben couldn't do because he can't guard Wade. This is where he differs from Bowen. Bowen can guard almost any player. He D on Dirk so far has been textbook.
Remember: If Wade was being guarded by Bowen, he wouldn't have off. Bowen would have put him in lock down mode.
DPOY = Bowen. This year.